Cyclic Loading Regimes Research Articles

Cyclic Mechanism Affects Lumbar Spine Creep Response.

This study aims to explore how cyclic loading influences creep response in the lumbar spine under combined flexion-compression loading. Ten porcine functional spinal units (FSUs) were mechanically tested in cyclic or static combined flexion-compression loading. Creep response between loading regimes was compared using strain-time histories and linear regression. High-resolution computed tomography (µCT) visualized damage to FSUs. Statistical methods, ANCOVA and ANOVA, assessed differences in behavior between loading regimes. Cyclic and static loading regimes exhibited distinct creep response patterns and biphasic response. ANCOVA and ANOVA analyses revealed significant differences in slopes of creep behavior in both linear phases. Cyclic tests consistently showed endplate fractures in µCT imaging. The study reveals statistically significant differences in creep response between cyclic and static loading regimes in porcine lumbar spinal units under combined flexion-compression loading. The observed biphasic behavior suggests distinct phases of tissue response, indicating potential shifts in load transfer mechanisms. Endplate fractures in cyclic tests suggest increased injury risk compared to static loading. These findings underscore the importance of considering loading conditions in computational models and designing preventive measures for occupations involving repetitive spinal loading.

Intermittent cyclic stretch of engineered ligaments drives hierarchical collagen fiber maturation in a dose- and organizational-dependent manner

Hierarchical collagen fibers are the primary source of strength in tendons and ligaments; however, these fibers largely do not regenerate after injury or with repair, resulting in limited treatment options. We previously developed a static culture system that guides ACL fibroblasts to produce native-sized fibers and early fascicles by 6 weeks. These constructs are promising ligament replacements, but further maturation is needed. Mechanical cues are critical for development in vivo and in engineered tissues; however, the effect on larger fiber and fascicle formation is largely unknown. Our objective was to investigate whether intermittent cyclic stretch, mimicking rapid muscle activity, drives further maturation in our system to create stronger engineered replacements and to explore whether cyclic loading has differential effects on cells at different degrees of collagen organization to better inform engineered tissue maturation protocols. Constructs were loaded with an established intermittent cyclic loading regime at 5 or 10 % strain for up to 6 weeks and compared to static controls. Cyclic loading drove cells to increase hierarchical collagen organization, collagen crimp, and tissue tensile properties, ultimately producing constructs that matched or exceeded immature ACL properties. Further, the effect of loading on cells varied depending on degree of organization. Specifically, 10 % load drove early improvements in tensile properties and composition, while 5 % load was more beneficial later in culture, suggesting a shift in mechanotransduction. This study provides new insight into how cyclic loading affects cell-driven hierarchical fiber formation and maturation, which will help to develop better rehabilitation protocols and engineer stronger replacements. Statement of significanceCollagen fibers are the primary source of strength and function in tendons and ligaments throughout the body. These fibers have limited regenerate after injury, with repair, and in engineered replacements, reducing treatment options. Cyclic load has been shown to improve fibril level alignment, but its effect at the larger fiber and fascicle length-scale is largely unknown. Here, we demonstrate intermittent cyclic loading increases cell-driven hierarchical fiber formation and tissue mechanics, producing engineered replacements with similar organization and mechanics as immature ACLs. This study provides new insight into how cyclic loading affects cell-driven fiber maturation. A better understanding of how mechanical cues regulate fiber formation will help to develop better engineered replacements and rehabilitation protocols to drive repair after injury.

Experimental and numerical study of locking steel plate damper for seismic resistance

In this paper, a new metal energy dissipator named locking steel plate damper (LSPD) is proposed for structural seismic applications. The damper is easy to fabricate and convenient to install and replace. The LSPD consists of two locking steel plates with energy dissipating steel rings and an outer shell plate for peripheral restraint and steel ring reset. Experiments were conducted using a proposed static cyclic displacement loading regime, which loaded the two specimens. The results of experiment showed that the damper possessed excellent energy dissipation capability. Thirteen comparison models were designed by varying the radius, thickness and width of the ring and FE simulations were carried out. By comparing the simulation results of the 13 models, the effects of the steel ring design parameters on the energy dissipation capacity of the damper are summarized. Finally, the suggested formulas for the yield displacement and the practical formulas for the initial stiffness of the LSPD are presented through theoretical derivation and parametric analysis. The average error between theoretical and simulated values for the 13 models was 2.11%, with a maximum error of 7.33%, which provide reliable suggestions for the design and fabrication of the damper.

Centrifuge testing on ordinary and hybrid suction caissons subjected to cyclic lateral loading

Hybrid Suction Caissons (HSCs) are innovative structures that amalgamate a shallow foundation (mat or skirted) with an internal caisson. The results of 40g centrifuge tests conducted on the Ordinary Suction Caisson (OSC) and two HSC types installed in medium-dense saturated sand, enduring long-term lateral cyclic loading (600 cycles), are analyzed and discussed in this paper. This research incorporates combined cyclic loading tests, encompassing one-way and two-way cycles in a singular examination to simulate the typhoon and service conditions before and after. The major findings include: (i) HSC, compared to OSC, can effectively harness accumulated rotations of the foundation induced by both one-way and two-way cyclic loading, (ii) adding an outer skirt to HSC, attached to an inner caisson and mat foundation, reduces considerably accumulated rotations induced by one-way cycles, (iii) cyclic loading does not change the unloading stiffness of OSC and HSC without an outer skirt, while increases the unloading stiffness of HSC with an outer skirt, and (iv) analyzing and designing OWT foundations should consider the combined cyclic loading scenario, rather than solely relying on one-way or two-way cyclic loading regimes. Based on the results, a power formula is proposed for estimating caissons' rotations stemming from long-term cyclic loading.

Development of a high-energy centrifuge model impact hammer for pile-driving

The offshore wind energy industry continues to expand rapidly around the world in response to the demand for clean energy. Research to investigate monopile performance under cyclic lateral loading needs to replicate the installation process as well as the cyclic loading regimes. This has provided the impetus for the development of model pile driving hammers for use in geotechnical centrifuges. This paper presents a new model-scale centrifuge impact hammer that is capable of in-flight driving of large-diameter piles into dense sediments with the flexibility of varying the energy during a test for a more controlled installation. The new hammer is activated by a pair of rotating cams, improving on the pneumatically activated hammer developed in the 1980s, giving greater energy and much better reliability. This paper provides full details of the hammer, together with data obtained at 80g acceleration, driving prototype 4 m wide (50 mm in model scale) piles into dense, dry sand to depths of over 20 m (over 5D) in <1000 blows.

Behaviour of small-scale glulam timber connections with slotted-in steel plates and dowel-type fasteners reinforced with self-tapping screws

Braced frames are a common lateral force-resisting system in mass timber structures. In timber braced frames, timber-steel dowel connections are relied upon to provide ductility and energy dissipation capacity under earthquake loads. However, the ductility and energy dissipation capacity of these connections can be limited by the onset of a brittle failure mechanism (e.g., row-shear or group tear-out) prior to significant dowel yielding. This paper presents an experimental campaign investigating the structural performance of timber-steel dowelled connections reinforced with self-tapping screws. Twelve connections were tested; with 8 tested under monotonic loading and 4 tested under a cyclic loading regime. The tested connections included two different fastener diameters of 11 mm and 16 mm, with one or two internal steel plates, both with and without reinforcing screws designed to prevent brittle shear failure. The results demonstrate that the reinforcing screws are most effective for improving the ductility and energy dissipation for connections with similar design values of dowel yield and row shear capacities. In addition, the increases in ductility and energy dissipation with reinforcement were greatest for connections with high slenderness (defined as the ratio of dowel diameter to timber thickness) dowels. There was little improvement in the ductility of connections whose design capacity was dominated by row shear, although there was improvement in the energy dissipation of the connections. Overall, results of this study demonstrate the potential for using self-tapping screws to reinforce steel dowel connections and improve the seismic performance of mass timber braced frames.

Mechanical Properties of 6061 Aluminum Alloy under Cyclic Tensile Loading

During the service process of an aluminum alloy structure, its complex deformation zone experiences repeated loading problems such as repeated tension, compression, bending and reverse bending. At the same time, the cyclic loading and heat treatment process also have a certain impact on the mechanical properties of aluminum alloy extruded tubes. Therefore, the study of heat treatment process parameters has important engineering and practical value for the mechanical properties of aluminum alloy extrusion tubes under cyclic loading conditions. The experiment takes 6061-T6 aluminum alloy extruded tubes as the research objects. In the study, heat treatment and cyclic tensile tests were carried out on 26 aluminum alloy specimens to study the effects of different heat treatment parameters (such as heating temperature, holding time, and cooling method) on the stress–strain hysteresis curves, stress characteristics, hysteretic energy, skeleton curves and failure characteristics of the alloy under the same loading system. In addition, different cyclic tensile tests were carried out on 20 aluminum alloy samples without secondary heat treatment to discuss the effects of different cyclic loading regimes on the mechanical properties of the alloy. The research results indicate that the effect of heating temperature on the cyclic loading performance of the alloy is greater than that of the holding time, and the effect of the cooling method on the cyclic loading performance of the alloy is not obvious. A cyclic tensile loading regime has a significant impact on the strength, elongation and hysteresis energy of the alloy. The hysteretic behavior of the alloy during cyclic tensile loading depends on the applied stress level and loading history. As the number of cycles increases, the shape of the hysteresis curve tends to be stable, but there is no monotonic relationship between the number of cycles loaded and the hysteresis energy.

Convergence Check Phase-Field Scheme for Modelling of Brittle and Ductile Fractures

The paper proposes a novel staggered phase-field framework for modelling brittle and ductile fractures in monotonic and cyclic loading regimes. The algorithm consists of two mesh layers (displacement and phase field) and a single special-purpose, user-defined finite element, which controls global convergence of the coupled problem and passing of the solution variables between mesh layers. The proposed algorithm is implemented into FE software ABAQUS. For the problem of high cyclic fatigue, a cycle-skipping scheme is also introduced. The proposed methodology is verified on the usual benchmark examples. Small-strain theory is applied, but it has been demonstrated that extension to large strains is straightforward using only the ABAQUS built-in option. The efficiency and stability of the proposed framework was proven by comparison of computational time and the number of iterations per increment in the RCTRL scheme.

Bond-slip performance of seawater sea sand concrete filled filament wound FRP tubes under cyclic and static loads

Adequate bond strength of concrete filled tubes is required to ensure full composite action and prevent premature bond failure before ultimate bending capacity is reached. This study investigates the bond strength and bond slip mechanisms of FRP tubes filled with seawater sea sand concrete (SWSSC) under static and cyclic axial loads using a push-out test. Glass and carbon fibre reinforced polymer (FRP) and two different diameters (100 mm and 165 mm) were tested to investigate the effect of changing parameters on the bond strength. Each group of specimen was tested under static load (SL) and various different cyclic loading (CL) regimes. An ANSYS FE model was created to simulate a static pushout test for FRP SWSSC composites under varying parameters to quantify the induced tube and confinement stress. Confinement and accumulated damage were found to be the two main factors determining the change in bond strength between cyclic and static load conditions. The high active confinement of the smaller diameter GFRP tubes resulted in a slight increase in bond strength for most samples under CL. The larger diameter CFRP tubes generally exhibited a slight drop in bond strength under CL due to the more pronounced effects of accumulated interface damage.

Memory surfaces separating the processes of monotonous and cyclic loads

The processes of elastoplastic deformation of structural materials can consist of a sequence of monotonous and cyclic loading regimes, in which peculiar effects and features arise. Mathematical modeling of such processes, as well as resource assessment and forecasting, is a very difficult task. In addition, the analysis of transient processes from cyclic to monotonous and from monotonous to cyclic shows the need to separate these processes. Based on the analysis of the results of experimental studies of samples of stainless steel 12Х18Н10T under a rigid (controlled deformation) deformation process, which is a sequence of monotonic and cyclic loading modes, under conditions of uniaxial tension-compression at normal temperature, the features and differences in the processes of monotonic and cyclic loading are revealed. To describe these features and separate the processes of monotonic and cyclic loading modes in the theories of plastic flow with combined hardening, various variants of memory surfaces are introduced. An analysis of the results of experimental studies of stainless steel showed that in the space of the plastic strain tensor, the size of the memory surface is determined by the range of plastic strains, and the position of the center is determined by the values of average plastic strains under cyclic loading. Various variants of the memory surface are considered, their capabilities and disadvantages are identified, and the most adequate variant of the memory surface is determined. To confirm the operability of this version of the memory surface, together with the equations of the Bondar plasticity model, the calculated and experimental results were compared and a reliable agreement was obtained between these results both in terms of the kinetics of the stress-strain state and in terms of the number of cycles to failure.

Seismic behavior of a novel RSSC-SPSW: An experimental and numerical study

Self-centering steel plate shear walls (SC-SPSWs) offer superior seismic properties if properly designed. This paper deals with experimental and numerical studies of Ring-shaped Self-Centering Steel Plate Shear Walls (RSSC-SPSWs). For this purpose, a SC-SPSW specimen previously tested up to a drift of 2.5% by Clayton et al. (2012) was selected, verified in the Abaqus environment, and simulated in the same software package to obtain 23 numerical models by cyclically changing the thickness, topology, and steel type of the web plate. One model, exhibiting a better seismic performance than the control was chosen for constructing a 2/3-scale experimental specimen that was subjected to a lateral cyclic loading regime. Results revealed that the RSSC-SPSW specimen proved energy dissipation and peak strength by 2.6 and 3.0 times, respectively, higher than those recorded for the control. It was also observed that, despite its increased web plate thickness, the specimen retained its self-centering behavior, which was attributed to the fact that neither did the web plate fail nor did its strength decline throughout the experiment. Finally, the numerical model of the experimental specimen was simulated cyclically up to a drift of 5% in the Abaqus software to study the failure model, buckling, and necking, which verified an acceptable agreement between the predicted and experimental results.

Cyclic loading regime considered beneficial does not protect injured and interleukin-1-inflamed cartilage from post-traumatic osteoarthritis

Injurious overloading and inflammation perturbate homeostasis of articular cartilage, leading to abnormal tissue-level loading during post-traumatic osteoarthritis. Our objective was to gain time- and cartilage depth-dependent insights into the early-stage disease progression with an in vitro model incorporating for the first time the coaction of (1) mechanical injury, (2) pro-inflammatory interleukin-1 challenge, and (3) cyclic loading mimicking walking and considered beneficial for cartilage health. Cartilage plugs (n = 406) were harvested from the patellofemoral grooves of young calves (N = 6) and subjected to injurious compression (50% strain, rate 100%/s; INJ), interleukin-1α-challenge (1 ng/ml; IL), and cyclic loading (intermittent 1 h loading periods, 15% strain, 1 Hz; CL). Plugs were assigned to six groups (control, INJ, IL, INJ-IL, IL-CL, INJ-IL-CL). Bulk and localized glycosaminoglycan (GAG) content (DMMB assay, digital densitometry), aggrecan biosynthesis (35S-sulfate incorporation), and chondrocyte viability (fluorescence microscopy) were assessed on days 3–12. The INJ, IL, and INJ-IL groups exhibited rapid early (days 2–4) GAG loss in contrast to CL groups. On day 3, deep cartilage of INJ-IL-CL group had higher GAG content than INJ group (p < 0.05). On day 12, INJ-IL-CL group showed more accumulated GAG loss (normalized with control) than INJ-IL group (average fold changes 1.97 [95% CI: 1.23–2.70]; 1.66 [1.42–1.89]; p = 0.007). Aggrecan biosynthesis increased in CL groups on day 12 compared to day 0. Despite promoting aggrecan biosynthesis, this cyclic loading protocol seems to be beneficial early-on to deep cartilage, but later becoming incapable of restricting further degradation triggered by marked but non-destructive injury and cytokine transport.

Achieving 1 GPa fatigue strength in nanocrystalline 316L steel through recovery annealing

Nanostructured metals offer an improved fatigue limit and high cycle fatigue performance compared to their microcrystalline counterparts. However, even the small cyclic plastic strain amplitudes present at these cyclic loading regimes can induce grain growth, a prerequisite for fatigue crack initiation. Retarding cyclically induced grain growth, for instance by alloying, should thus further improve the fatigue performance. Here, we followed a different strategy and investigate the role of recovery heat treatments, known to shift the onset of plasticity to higher stress levels. Indeed, we observe for the recovered specimens an unprecedented increase of the fatigue limit, reaching for 316L steel values of almost 1 GPa at a stress ratio of R=-1. First experiments further indicate that this strategy could also be used to improve the fatigue limit of conventionally cold worked austenitic structures.

In-plane lateral behaviour of PVC modular concrete form squat walls: Experimental and numerical study

The in-plane lateral performance of modular concrete form squat walls comprising prefabricated Polyvinyl Chloride (PVC) permanent forms and reinforced concrete cores was experimentally and numerically undertaken. The PVC encasement make additional confinement to the reinforced concrete core that makes the formwork attractive, however, the interaction between the encasement and the concrete make an irregular internal concrete core and therefore further studies are required. Eleven wall specimens of different aspect ratios ranging from 0.5 to 2.0 were subjected to incrementally increasing monotonic drifts to failure after imposing eccentric vertical loads as indicative of gravity loading conditions. Two samples were further selected and investigated by adopting push-out tests to measure in-plane shear capacity of PVC form walls. The experimental measures including concrete crack propagation and crushing, loads and displacements pertinent to capping and failure stage, and ductility capacity were discussed. After stripping the form off, a failure mode in walls demonstrated discontinuity in the concrete crack propagation due to penetration of the form web into the concrete core which did not act as a solid concrete wall. Finite element simulations were undertaken according to suggested modelling techniques and the credibility of the numerical method was investigated through comparison with experiment results. Implications of change in design parameters including axial load ratio, wall aspect ratio, concrete strength, vertical, horizontal reinforcement ratio, and cyclic loading regime were further examined through a detailed parametric study. It demonstrated that the peak lateral load capacity and post-peak negative stiffness of PVC form squat concrete walls were highly influenced by axial load ratio. The influence of concrete strength on peak lateral response of the walls was in direct proportion to the axial load ratio. Increasing horizontal reinforcement ratios showed the modest influence on the peak lateral load capacity of the walls.

Design method of flexural capacity of BFRP bar reinforced ecological high ductility cementitious composites beam

Steel expansion joints are damaged under traffic loading, and bridge deck link slab made by basalt fiber reinforced polymer (BFRP) bar reinforced ecological high ductility cementitious composites (Eco-HDCC) can be used to replace the expansion joints. To provide the structural design guideline of bridge deck link slab, experimental study and theoretical analysis of BFRP bar reinforced Eco-HDCC bending beam were conducted. The diameter of BFRP bar and cover thickness were considered. Monotonic and cyclic loading modes were compared. When the diameter is within 8 mm ∼ 16 mm and the cover thickness is within 25 mm ∼ 35 mm, the peak load of beam increases as the diameter increases or the cover thickness decreases. Monotonic and cyclic loading regimes have little effects on the peak load. Before the beam cracks, diameter and cover thickness have little effects on the strain of BFRP bar and compressive strain of Eco-HDCC. After the beam cracks and under the same load, both the strain of BFRP bar and compressive strain of Eco-HDCC decrease as the diameter increases. Loading regime has little effect on the envelope curves of load-BFRP bar strain and load-Eco-HDCC compressive strain. Calculation formulas of flexural capacity for under-reinforced beam, balanced-reinforced beam and over-reinforced beam are established as the tensile stress–strain relationship of Eco-HDCC is involved. Compared with the test results, the calculation formulas of flexural capacity are feasible.

Steel fatigue under non-stationary cyclic loading with low cycle overloads

The regularities and mechanisms of the elastoplastic strain of structural steels of two different types under two-stage cyclic loading regime conditions combining multicycle fatigue loading and hard elastoplastic strain under repeated overloading are considered. Based on experimental results and metallographic studies, repeated elastoplastic overloads on changes in the structural state of the material, mechanisms of fatigue damage accumulation, and lifetime indicators compared to the stationary process of cyclic loading are evaluated. It is shown that the combination of multicycle loading modes and low-cycle overloading leads to a change in fatigue resistance mechanisms of steels and changes in fatigue life depending on the loading history. Predict the effect of pre-elastoplastic loading of different types of metals, a change ratio in lifetime depending on the parameters of the two-step cyclic loading regime is proposed.

Calculation of fatigue fracture in structural elements using a multimode damage model

The problem of nucleation and development for the fatigue fracture process in element of aircraft structure is solved using previously developed cyclic damage model. The model contains the evolution equation for the damage function depending on stress state and amplitudes of the cyclic loads. On this basis, calculations of the initiation and development of crack-like fracture zones are carried out for an aircraft structure element of a disk with a blade in a flight loading cycle (HCF mode). The damage function was calculated based on the elastic solution for the element of structure loaded by centrifugal forces in disk and blade and aerodynamical pressure on blade. An alternative cyclic loading regime associated with high-frequency vibrations of the blades was investigated. Fatigue fracture in this process corresponds to the VHCF mode. Simulation of the combined cyclic loading mode was also carried out. In all these modes, the real time of the nucleation and development of quasi-cracks was estimated up to reaching the observed disk surface.

ЧИСЛЕННОЕ МОДЕЛИРОВАНИЕ УСТАЛОСТНОЙ ДОЛГОВЕЧНОСТИ ДЕТАЛЕЙ АВИАЦИОННЫХ ГТД ПРИ ЦИКЛИЧЕСКОМ ДВУХЧАСТОТНОМ НАГРУЖЕНИИ

The problem of assessing the resource characteristics of responsible engineering facilities, taking into account the peculiarities of operational loading modes, is discussed. The processes of fatigue durability of polycrystalline structural alloys under cyclic two-frequency loading (with the combined action of mechanisms of low and multi-cycle fatigue) are considered. A mathematical model describing the processes of cyclic elastoplastic deformation and accumulation of fatigue damage in structural alloys under multiaxial disproportionate modes of combined thermomechanical loading has been developed from the modern positions of damaged medium mechanics and fracture mechanics. The model consists of three interrelated parts: relations determining the cyclic elastic-plastic behavior of the material, taking into account the dependence on the destruction process; evolutionary equations describing the kinetics of fatigue damage accumulation; criteria for the strength of the damaged material. The variant of the defining elastic-plasticity relations is based on the idea of the yield surface and the principle of gradiency of the velocity vector of plastic deformations to the yield surface at the loading point. This version of the equations of state reflects the main effects of cyclic elastic-plastic deformation of the material for arbitrary folded loading trajectories. The variant of kinetic equations of fatigue damage accumulation is based on the introduction of a scalar damage parameter, is based on energy principles and takes into account the main effects of formation, growth and fusion of microdefects under arbitrary complex cyclic loading regimes. A joint form of the evolutionary equation of fatigue damage accumulation in the areas of low- and multi-cycle fatigue is proposed. As a criterion of the strength of the damaged material, the condition of reaching the critical value of the damage value is used. The results of numerical simulation of fatigue durability of a compact sample (model of the disk deflector of the high pressure turbine of an aviation gas turbine engine) are presented with cyclic two-frequency loading. The results of the comparison of the calculated and experimental data showed that the proposed model qualitatively and with the accuracy necessary for practical calculations quantitatively describes the fatigue life of structural elements under cyclic two-frequency loading.

Effects of notch-load interactions on the mechanical performance of 3D printed tool steel 18Ni300

The capability of additive manufacturing to produce parts with complicated geometrical features is one of the unique advantages of this technology over traditional production methods. However, the intricate interaction between concentrated stress fields imposed by various geometrical profiles, inherent defects, and external loads must be comprehensively recognized to leverage the aforementioned ability. Consequently, this study investigated the simultaneous effects of macroscopic notches and microscale defects on the performance of tool steel 18Ni300 under quasi-static and cyclic loading regimes. The specimens were manufactured using the laser-powder bed fusion technique, a common method for industrial applications that rely on metals. Eleven (horizontally built) sample designs, consisting of external or internal notches with different characteristics, were considered in this study to ensure a comprehensive comparison. The results showed that the surface quality was slightly higher along the notch roots than in the other areas. All the notches, regardless of their types, reduced ductility. Notch strengthening was generally observed in the notched samples under quasi-static loads. However, the degree of strengthening was directly related to the stress concentration factor, unlike for typical conventional metals. This unexpected behavior was attributed to the inherent defects in the manufacturing process. The surface defects at the notch roots played a dominant role in governing fatigue failures. A modification of the Murakami approach was proposed to estimate the fatigue life of notched components fabricated via additive manufacturing. Finally, the applicability of the Solberg–Berto diagram to predict the failure locations in horizontally manufactured samples was evaluated. The diagram largely agreed with the experimental data obtained from this study.

Influence of Loading Pressure and Sample Preparation on Ionic Concentration and Resistivity of Pore Solution Expressed from Concrete Samples

AbstractPore solution expression is an established method to obtain samples of the liquid phase from cementitious systems. This experimental method applies pressure to a cementitious sample, forcing its liquid phase out of the pores. By collecting and studying the liquid phase in cementitious systems, it is possible to obtain information on its ionic concentrations. The ionic concentrations can be used for modeling calibrations and to estimate the resistivity of the pore solution. When the bulk resistivity of concrete is normalized by the pore solution resistivity, it is possible to determine the formation factor. The formation factor is related to the transport properties of the concrete and, as such, it can be used to estimate the rates of transport of ionic species within a concrete structure. The formation factor is currently being included in AASHTO PP84, Standard Practice for Developing Performance Engineered Concrete Pavement Mixtures, as an indicator of transport properties for quality control operations. Pore solution expression is included as one of the available procedures of AASHTO PP84-19 to determine the pore solution electrical resistivity. Previous studies on paste and mortar samples have demonstrated that increased loading pressure during the pore solution expression might impact the final ionic concentrations of the expressed solution. This study aims to verify if the pore solutions of concrete specimens are also influenced by the selected loading pressure and whether the potential consequent change in the measured ionic concentrations of the solution also has an impact on its resistivity. No appreciable trend in increased solubility was observed for the range of applied normal pressures between 600 and 985 MPa. Cyclic loading regimes increased the variability of alkali solubility. Sample preparation, in some cases, influenced the water content of the sample and induced unwanted alteration on the ionic concentrations of the mixtures under study.